[Issue #719] Adding shouldUseCredentialStorage property to AFURLConnectionOperation /thanks Xihe Yu

AFNetworking/AFURLConnectionOperation.h

@@ -126,9 +126,16 @@
 @property (readonly, nonatomic, assign) NSStringEncoding responseStringEncoding;
 
 
-///--------------------------------
-/// @name Accessing URL Credentials
-///--------------------------------
+///-------------------------------
+/// @name Managing URL Credentials
+///-------------------------------
+
+/**
+ Whether the URL connection should consult the credential storage for authenticating the connection. `YES` by default.
+ 
+ @discussion This is the value that is returned in the `NSURLConnectionDelegate` method `-connectionShouldUseCredentialStorage:`.
+ */
+@property (nonatomic, assign) BOOL shouldUseCredentialStorage;
 
 /**
  The credential used for authentication challenges in `-connection:didReceiveAuthenticationChallenge:`.

AFNetworking/AFURLConnectionOperation.m

@@ -145,6 +145,7 @@ static inline BOOL AFStateTransitionIsValid(AFOperationState fromState, AFOperat
 @dynamic inputStream;
 @synthesize outputStream = _outputStream;
 @synthesize credential = _credential;
+@synthesize shouldUseCredentialStorage = _shouldUseCredentialStorage;
 @synthesize userInfo = _userInfo;
 @synthesize backgroundTaskIdentifier = _backgroundTaskIdentifier;
 @synthesize uploadProgress = _uploadProgress;
@@ -206,6 +207,8 @@ static inline BOOL AFStateTransitionIsValid(AFOperationState fromState, AFOperat
     
     self.request = urlRequest;
 
+    self.shouldUseCredentialStorage = YES;
+    
     self.outputStream = [NSOutputStream outputStreamToMemory];
 
     self.state = AFOperationReadyState;
@@ -573,6 +576,10 @@ didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
     }
 }
 
+- (BOOL)connectionShouldUseCredentialStorage:(NSURLConnection __unused *)connection {
+    return self.shouldUseCredentialStorage;
+}
+
 - (NSInputStream *)connection:(NSURLConnection __unused *)connection
             needNewBodyStream:(NSURLRequest *)request
 {